tbuckley/cabot-search huggingface dataset:
Extracellular and intracellular magnesium concentrations in asthmatic patients
Authors: HW de Valk, PT Kok, A Struyvenberg, HJ van Rijn, None Haalboom, J Kreukniet, JW Lammers
Journal: European Respiratory Journal (1993)

Magnesium deficiency is associated with increased contractility of smooth muscle cells. Since contractility of bronchial smooth muscle is important in patients with asthma, magnesium deficiency could negatively influence the clinical condition. We wanted to assess whether magnesium deficiency exists in patients with asthma. Extracellular (plasma) and intracellular (erythrocytes and mononuclear leucocytes) concentrations of magnesium were determined in 20 mildly symptomatic patients with asthma and compared to 20 healthy controls. In asthmatic patients, the mean +/- SD magnesium level in plasma was 0.81 +/- 0.05 mmol.l-1, in erythrocytes 0.20 +/- 0.02 fmol.cell-1, and in mononuclear leucocytes 5.10 +/- 2.55 fmol.cell-1; these values did not differ significantly from those of the healthy controls: 0.79 +/- 0.06 mmol.l-1, 0.19 +/- 0.02 fmol.cell-1, and 4.61 +/- 1.75 fmol.cell-1, respectively. No evidence for the existence of a magnesium deficit needing chronic magnesium supplementation was, thus, found in these patients.
Abstract P1117: Transcriptional Changes In Failing Hearts In A South Asian Cohort Capture Molecular Pathophysiology Underlying Maladaptive Remodelling And Reflect A Consistent Disease Gene Signature
Authors: Amit Anand, Samuel Hellings, Shilpa Garg, Julius Punnen, U M Nagamalesh, Sabariya Selvam, Bagirath Raghuraman, Onkar Date, Senthil Kumaran, Pradeep Narayan, Ankita Udwadia, David A Gordon, Lei Zhao, Jyoti Gulia
Journal: Circulation Research (2022)

Heart failure (HF) is a leading cause of death worldwide and research focused on human cardiac tissue provides insights into underlying disease mechanisms. In this study, we performed transcriptome analyses on cardiac tissue from 21 South Asian (SA) HF patients and compared them with 21 controls without HF. The aim was to i) probe dysregulated genes and pathways in HF and ii) identify a core HF gene signature conserved across etiologies and ethnicities. Gene set enrichment analyses on dysregulated genes (DGs) showed positive enrichment of Gene Ontology terms for ECM remodelling, immune signalling and negative enrichment of terms like cardiac conduction, muscle contraction reflecting altered molecular signalling and cellular cross-talk in failing hearts. The immune cell signatures among the DGs suggest changes in immune milieu which correlates with altered immune signalling pathways. Although poor concordance in DGs across studies on HF transcriptome is well documented, evidence on stratification potential of select DGs is still preliminary. Using an independent component analysis and a machine learning based workflow, we identified gene signatures from two cohorts (SA, GSE116250) independently. We refined these into a core signature after cross validating their stratification potential and by removing the genes with low potential. The core signature effectively separated HF from control samples in SA, GSE116250 and other cohorts potentially reflecting central elements underlying end stage HF. In summary, the transcriptome analyses from SA HF cohort highlights the pathways reflecting HF pathophysiology and reiterates conserved themes across public HF cohorts.
Abstract P1075: Elucidate The Mechanism Driving The Imbalance Between BMPs And Activin/Gdfs Signaling In Pulmonary Arterial Hypertension
Authors: Kit Yee Chu
Journal: Circulation Research (2022)

Transforming Growth Factor-beta (TGF-β) family signaling is involved in Pulmonary Arterial Hypertension (PAH) in humans. PAH is a rare, highly morbid disorder characterized by dysregulated pulmonary vascular remodeling, elevated pulmonary vascular resistance, and the progressive obliteration of the pulmonary arteriolar circulation. The progression of PAH is largely influenced by the proliferation and migration of the pulmonary smooth muscle cells (PASMCs) and pulmonary endothelial cells (PAECs). While the exact mechanism is not understood, there is evidence that germline mutations in the BMPRII gene, one of the TGF-β family type II receptors, is present in PAH patients. Due to the functional similarity of BMPRII and type II Activin receptors ACVR2A and ACVR2B, they interact with overlapping TGF-β family ligands to activate either the SMAD 1/5/8 or SMAD 2/3 signaling. In the pulmonary vasculature, the BMP-9 ligand regulates cell proliferation by binding to type I receptors, ALK-1 and BMPRII, to activate SMAD 1/5/8 signaling. In PAH, there is a decrease in SMAD 1/5/8 signaling and an increase in SMAD 2/3 signaling. However, what causes the signaling switch is still unknown. In our lab, we found out that BMPRII and ACVR2A bind TGF-β ligands with nearly identical geometry based on our crystal structures. Both of the receptors contain a conserved hydrophobic hot spot within the ligand binding pocket. We found that the BMPRII ligand binding domain may exhibit greater flexibility than ACVR2A. We also investigated eight soluble BMPRII extracellular domain mutants and expressed them as BMPRII-Fc fusion proteins (BMPRII-Fc variants). Using surface plasmon resonance, we observed four of the BMPRII-Fc variants bind to high affinity ligands, such as BMP9, BMP10, Activin B and Activin A. In reporter gene assays, we found these BMPRII-Fc variants act as a ligand trap and attenuate BMP9 and BMP10-mediated SMAD1/5/8 signaling in HEK293 cells. Interestingly, they did not inhibit Activin B-mediated SMAD2/3 signaling. In conclusion, our findings show gain of function of specific BMPRII mutations and suggest that imbalances between SMAD1/5/8 and SMAD2/3 signaling may lead to PAH progression.
Abstract P3080: S100A8/9 Is A Key Regulator For Normal Heart Function During <i>Pseudomonas Aeruginosa</i> Infection
Authors: Naresh Kumar, Matthew J Pestrak, Qian Wu, Sheri Dellos-Nolan, Rajnikant Shukla, Cortney F. Mitchem, Lianbo yu, William Lafuse, Prabhakara R Nagareddy, Latha P. Ganesan, Daniel Wozniak, Murugesan V Rajaram
Journal: Circulation Research (2022)

Rationale: P. aeruginosa ( P.a ) infection can cause severe pneumonia in ICU patients that leads to cardiac inflammation and cardiac dysfunction. Growing evidence indicates that a large number of neutrophils are recruited to the site of P.a. infection and releases S100A8/9 into the microenvironment. S100A8/9 has been shown to activate both the immune system (TLR4/RAGE) and has bactericidal properties. Often, hyperactivation of the inflammatory responses by S100A8/9 causes cardiac inflammation and dysfunction. Thus, we hypothesize that excessive production of S100A8/9 restrict bacterial growth and enhances the host immune response in order to control the infection and preserve heart function. Objective: To identify the mechanism of S100A8/9 mediated cardiac inflammation and cardiac dysfunction during P. aeruginosa infection. Methods and Results: To investigate the role of S100A8/9 in cardiac inflammation and cardiac dysfunction, we infected wild type (WT) and S100A8/9KO mice with P.a. intranasally. We monitored bodyweight at 24h intervals and measured weight loss, survival, and bacterial burden in the lungs and heart. We performed multicolor flow cytometry on BAL cells and heart cells for immune cell phenotyping and ELISA for cytokine levels. Also, we measured cardiac electric activity (EKG) and heart function (echocardiography). We found that bacterial burden in the lungs and heart was higher in S100A8/9KO mice than in WT, which correlated with increased mortality. We found severe cardiac electrical abnormalities (second-degree AV block) in S100A8/9KO mice and left ventricular dysfunction. However, there was no significant difference in the BALF immune cell phenotypes of both S100A8/9KO and WT infected mice. Finally, the S100A8/9 inhibitor enhanced the survival of P.a. infected mice. Conclusion: Our data demonstrate that neutrophil recruitment and release of S100A8/9 is critical to control bacterial growth in the lungs, however, uncontrolled neutrophil accumulation leads to excessive production of S100A8/9. Hyperactivation of the immune system by excessive S100A8/9 leads to systemic inflammation and bacterial dissemination of the heart. Furthermore, our studies revealed that blocking S100A8/9 receptor binding enhances the survival of mice during P.a. infection.
Abstract P2043: Interleukin-1 Blockade Restores Exercise Capacity After Non-reperfused Acute Myocardial Infarction In The Mouse.
Authors: Habeebah Vohra, Pratyush Narayan, Eleonora MEZZAROMA, Benjamin W Van Tassell, Antonio Abbate, Stefano Toldo
Journal: Circulation Research (2022)

Background: Acute myocardial infarction (AMI) is associated with an intense inflammatory response promoting progression to heart failure (HF), characterized by dyspnea, fatigue, exercise intolerance. Interleukin-1 (IL-1) is the prototypical inflammatory cytokine increased in AMI. IL-1 injections reduce exercise capacity in healthy mice. Whether IL-1 reduces exercise capacity after AMI is unknown. Hypothesis: IL-1 blockade preserves exercise capacity in mice with experimental AMI. Methods: Ten-week-old male CD1 mice (N=45) were trained to run on a treadmill. Baseline exercise capacity was assessed. Based on the distance run, the mice were divided into tertiles. Mice in the middle tertile underwent surgical ligation of the coronary artery. Ten mice survived and were randomly assigned to treatment with daily intraperitoneal injections with anakinra, a recombinant human IL-1 receptor antagonist (10 mg/kg, 0.2 ml, N=4), or 0.9% NaCl vehicle (N=6). We measured exercise capacity at 1, 2, and 4 weeks. Data were analyzed using T-test for unpaired groups and are presented as mean and standard error of mean. Results: Baseline exercise capacity was 217±16 and 230±16 m in the anakinra and vehicle groups, respectively. Exercise capacity was significantly reduced 1 week after surgery in both groups (-57±9% vs -60±7%, P=0.80; P&lt;0.01 vs respective baseline). By week 4, however, anakinra treatment significantly improved exercise capacity compared to the vehicle (+42±4% vs +8±7%, P&lt;0.001) (Figure). Conclusion: Non-reperfused AMI leads to a severe reduction in exercise capacity that is reversed by IL-1 blockade. These data support IL-1 as a therapeutic target for preventing HF after AMI.
Therapeutic compliance in asthma; its magnitude and implications
Authors: GM Cochrane
Journal: European Respiratory Journal (1992)

Failure to heed medical advice is common, but the precise extent is poorly understood and barely investigated. Factors leading to poor compliance are not known but claims of lack of education are frequently mentioned. However these have yet to be scientifically substantiated. The frequency of medication and social and economic factors, allied to poor communication, are probably involved but do not account for it entirely as non-compliance may vary between 20-80% of patient populations. Asthma mortality is not decreasing despite effective medication and increasingly there are worries that poor compliance may be a significant factor.
Abstract P1029: Improving Cardiomyocyte Cell Cycle Entry In Response To Direct Cell Cycle Stimulation Using A Novel Small Molecule Inhibitor Of P38
Authors: Riham R Abouleisa, Ahmad Gebreil, Aboubakr B Salama, Qinghui Ou, Nader E Abo-Dya, Bradford G Hill, Tamer Mohamed
Journal: Circulation Research (2022)

Background: Myocardial infarction is the leading cause of mortality globally, due in part to the limited ability of cardiomyocytes (CMs) to regenerate. Recently, we showed that overexpression of a combination of 4 cell cycle factors, CDK1, CDK4, cyclin B1, and cyclin D1 (collectively known as 4F), induced cell division in ~15% of post-mitotic mouse, rat, and human CMs. The aim of the current study is to identify novel small molecules that further augment CM cycle induction caused by the 4F. Methods and Results: We performed a drug screening of 30 chemical compounds with possible cell cycle regulatory activities using 60-day-old mature hiPS-CMs overexpressing the 4F and assessed the increase in EDU (DNA synthesis marker) and PHH3 (G2-M phase marker). The top hit was N-(4,6-Dimethylpyridin-2-yl)-4-(pyridin-4-yl)piperazine-1-carbothioamide (NDPPC). NDPPC showed a dose-dependent increase in the percentage of EDU and PHH3 positive nuclei in hiPS-CMs transduced with 4F. CMs transduced with 4F and treated with 1 μM NDPPC showed a significant increase in the percentage of EDU and PHH3 compared with vehicle (V)-treated CMs (PHH3; V: 20.41±2.02%, NDPPC: 33.75±3.9%, EDU; V: 18.24±1.7%, NDPPC: 30.81±2.1% n=6, p&lt;0.001). In Silico Drug-Target prediction showed that NDPPC could interact with p38 mitogen-activated protein kinase (P38), a critical negative regulator of mammalian cell cycle. Therefore, we overexpressed P38, in the presence and absence of NDPPC and 4F. As expected, overexpression of P38 in CMs inhibited 4F cell cycle induction, and treatment with NDPPC reversed the cell cycle inhibitory effect (in presence of 4F PHH3%; V: 20.38±0.97%, P38 overexpression+V: 11.02±1.3%, P38 overexpression+NDPPC: 23.62±2.79, n=4, P&lt;0.001). Knockdown of P38 showed a significant increase in the percentage of EDU and PHH3 positive nuclei in 4F treated CMs, and treatment with NDPPC did not show any further increase in cell cycle induction. These data indicate that NDPPC enhances the 4F cell cycle response in CMs through inhibition of P38. Conclusions: NDPPC is a novel inhibitor for P38. NDPPC is a promising drug to promote CM cell cycle response to the 4F. Further work in vivo is needed to test whether NDPPC could improve the 4F effect on cardiac function after ischemic injury.
Abstract P1047: Imatinib Attenuates Reperfusion Injury In A Rat Model Of Acute Myocardial Infarction
Authors: Lara S Konijnenberg, Laween Uthman, Andor Veltien, Carolien T Kuster, Tom T Luiken, Guus A De Waard, Kitty Lemmens-Hermans, Karin de Haas-Cremers, Mariska Kea-te Lindert, Deniz Daviran, Dick H Thijssen, Anat Akiva, Robin Nijveldt, Niels van Royen
Journal: Circulation Research (2022)

Background: Reperfusion of an occluded coronary artery is often accompanied by injury of the microvasculature (MVI), which portends a worse long term prognosis after an acute myocardial infarction (AMI). In previous experimental studies, the tyrosine-kinase inhibitor imatinib has shown to reduce vascular leakage and therefore could have a potential role to prevent MVI. This study aims to provide a potential therapeutic approach using imatinib to attenuate reperfusion injury. Methods: First, 16 isolated male Wistar rat hearts were randomly assigned to 10 μM imatinib or placebo and subjected to 40 min of global ischemia followed by 120 min of reperfusion ex vivo in a Langendorff setup. Global infarct size and mechanical function were assessed. Second, 25 male Wistar rats were randomly assigned to 30 mg/kg imatinib or placebo intravenously and subjected to 45 min of left anterior descending coronary artery ligation followed by 180 min of reperfusion in vivo. Cardiovascular magnetic resonance imaging was performed to assess infarct size and cardiac function. Subsequently, hearts were perfused ex vivo with a fluorescent vascular leakage tracer and used for fluorescence- and electron microscopy. Results: In isolated hearts, imatinib reduced global infarct size (imatinib 36.2±7.9 vs placebo 50.0±8.0% infarcted area/total area, p&lt;0.01), improved end diastolic pressure (imatinib 44.2±8.0 vs placebo 59.5±13.5 mmHg, p&lt;0.05) and rate pressure product recovery (imatinib 39.0±6.8 vs placebo 26.2±7.6% of baseline, p&lt;0.05). In vivo, imatinib reduced infarct size (imatinib 12.6±8.8 vs placebo 25.6±9.3% infarcted area/left ventricle, p&lt;0.01), but did not improve global cardiac function. At the end of reperfusion, imatinib showed lower vascular resistance, higher coronary flow and less microvascular leakage (all p&lt;0.05). At the ultrastructural level, imatinib showed better preserved microvascular integrity compared to placebo. Conclusion: This study provides evidence that imatinib attenuates reperfusion injury in an ex vivo and in vivo AMI rat model, mainly by protection of the coronary microcirculation. These data warrant future work to examine the potential of imatinib to reduce reperfusion injury in patients with AMI.
Abstract P2084: Determining The Role Of Rap1b In Megakaryocyte Survival
Authors: Audrey A Mattmiller, Jaclyn A Wisinski
Journal: Circulation Research (2022)

Platelet counts are tightly regulated through production by megakaryocytes and clearance by hepatocytes. Thrombotic risk and poor cancer prognosis correlate with platelet counts on the high and low ends of the normal range, respectively. Therefore, understanding the factors that regulate megakaryocyte survival and function are important for human health. The small GTPase, Rap1b increases in abundance as megakaryocytes mature and mediates survival in other cell types by preventing apoptosis. We hypothesize that disruption of the Rap1b gene in the megakaryocytic leukemia cell line, DAMI, will limit cell survival by increasing susceptibility to apoptosis. We used CRISPR/Cas to specifically disrupt the Rap1b gene, resulting in no detectable Rap1b protein in DAMI cells. Compared to wild-type DAMI cells, Rap1b knockout cells had nearly a 50% reduction in survival as measured by metabolic activity using an MTT-assay. To assess apoptosis susceptibility, we monitored mitochondrial membrane potential using the fluorescent sensor JC-1 and caspases activity using the Fluorochrome Inhibitor of Caspases (FLICA). These results suggest that Rap1b promotes megakaryocyte survival.
Abstract GS103: Extracellular Vesicles Function As An Alternative Disposal Pathway For Mitochondria In The Heart
Authors: Wenjing Liang, Rachel Diao, Rita Najor, Justin Quiles, Liguo Chi, Asa Gustafsson
Journal: Circulation Research (2022)

Cardiac myocytes require large amounts of energy supplied by mitochondrial oxidative phosphorylation to sustain contractile function in heart. Because mitochondria can turn into death-promoting organelles, cells have developed defense mechanisms against aberrant mitochondria that can cause harm to the cell. It is well established that dysfunctional mitochondria are sequestered by autophagosomes and subsequently delivered to lysosomes for degradation. Recent studies have identified that additional mechanisms of mitochondrial clearance exist in cells. However, these pathways all converge at the level of the lysosomes and it is not clear whether alternative mitochondrial quality control pathways exist when lysosomal function is compromised. We have discovered that mitochondria can also be secreted from cells in extracellular vesicles (EVs) when internal degradation pathways are impaired. Pharmacological disruption of lysosomal acidification or genetic disruption of autophagy leads to increased release of large and small EVs in vitro and in vivo. Proteomics and biochemical analyses confirm that the large EVs containing mitochondria originate from the endosomal pathway. Transmission electron microscopy confirmed the presence of mitochondria in the large EVs. Knockdown of Rab27, a small GTPase involved in trafficking of multivesicular bodies (MVB) to the plasma membrane, abrogates the release of EVs from cells. Rab7 is also present on MVB and is involved in promoting fusion between MVB and lysosomes. We found that inactivation of Rab7 on the MVBs reroutes the vesicles to the plasma membrane for secretion of cargo. Cardiac-specific deletion of Rab7 in mice also leads to increased release of large EVs from myocytes. Finally, autophagic activity in the heart is reduced with age and we confirmed that secretion of EVs is increased in aged (24-month old) mouse hearts compared to young (4-month old). Taken together, these findings suggest that secretion of impaired mitochondria in EVs is an alternative quality control pathway utilized by cells when lysosomal function is compromised.
Abstract P1024: 3d Cardiac Tissue Rings With Exogenous Extracellular Matrix As A Model For Cardiac Fibrosis
Authors: Natalie Weiss, Jacob Gershon, Tracy Hookway
Journal: Circulation Research (2022)

Introduction: Cardiac fibrosis, or excess deposition of extracellular matrix (ECM) within heart muscle, acts as a protective mechanism following cardiac injury, but causes long-term heart stiffening and impaired contraction. In vitro models aid in understanding cardiac disease mechanisms, but current fibrosis models lack (i) native-like ECM and (ii) interactions between multiple cardiac cell types. Objective: Our 3D model containing induced pluripotent stem cell-derived cardiomyocytes (iPSC-CM) and cardiac fibroblasts (CF) with exogenous ECM will reproducibly assess contractile changes under fibrotic conditions. Methods: Human GCaMP-encoded iPSC-CM (day 19) and CF (3:1) were combined in a custom agarose ring mold with collagen I (Col) (0.02 or 0.5 mg/mL), laminin (Lam) (0.01 mg/mL), both Col+Lam (0.03 mg/mL), Matrigel (0.03 mg/mL), or no ECM, n=5 for each condition. Concentrations were based on in vivo ratios of Col and Lam in literature. After 24 hours, cells self-assembled into 3D rings (Fig. 1a). Results: All conditions formed robust rings; average thickness = 460 μm (Fig.1b, c). Spontaneous beating resumed 48 hours after seeding. After 3 days in culture, Ca 2+ flux videos were captured; rings without ECM displayed shorter contraction durations, as did Col+Lam rings (Fig. 1d, e). This suggests that exogenous ECM in ratios found in healthy hearts may aid in contraction. Conclusion: This ring platform provides a reproducible cardiac fibrosis model with native-like ECM conditions and interactions between multiple cardiac cell types. Further assessments of ring stiffness and additional ECM conditions will enable this model to be used in therapeutic development.
Abstract P3056: Influence Of Maternal Diabetes And High Fat Diet On Myocardial Ketone Body Metabolism In The Offspring
Authors: Prathapan Ayyappan, Tricia D Larsen, Tyler C Gandy, Michelle L Baack
Journal: Circulation Research (2022)

Alteration in myocardial substrate utilization and energy metabolism is a well-known contributor to the pathogenesis of heart disease. Recent studies suggest the failing heart may benefit from ketone bodies as an energy source. Infants exposed to diabetic pregnancy are at higher risk of cardiomyopathy at birth and early onset cardiovascular disease (CVD) as adults. We showed fetal exposure to excess circulating fuels, especially to the combination of maternal high fat diet (HFD) and diabetes, exaggerates CVD risk through fuel-mediated mitochondrial dysfunction including complex I dysfunction. Diabetic pregnancy increases ketone body exposure in utero, but whether prenatal exposures impair myocardial metabolism of ketones postnatally remains unknown. The objective of this study was to determine whether neonatal rat cardiomyocytes (NRCM) exposed to maternal diabetes and HFD in utero can increase ketone oxidation as a preferred fuel source over glycolysis. To test our hypothesis, we developed a ketone stress test (KST) or modified extracellular flux analyses to compare real-time ß-hydroxy butyrate (ßOHB) metabolism in NRCM and myocardial expression of genes responsible for ketone and lipid metabolism. While control and combination exposed NRCM had similar basal respiration, the presence of ketone (4.5 mM) increased maximal respiration, spare respiratory capacity, and ATP-limited glycolytic rate in the combination exposed group. Interestingly, baseline proton efflux rate (PER) from lactate (anaerobic glycolysis) decreased while PER from CO 2 (aerobic glycolysis) increased in response to ketones in the combination exposed group. Expression of genes responsible for ketone body metabolism ( Hmgcs2 and Bdh1 ) was not different. The study uses a novel KST to analyze real-time ketone body metabolism and demonstrates myocardial ketone body metabolism is preserved and may be protective in the NRCM exposed to maternal overnutrition.